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Mosaic, chlorosis, brown spots, or roughness were found on Vigna marina and V. riukiuensis, which are salt-resistant wild relatives of cowpea (V. unguiculata) and adzuki bean (V. angularis), respectively, on Miyako Island, Japan. RNA-sequencing was performed to identify both cucumber mosaic virus (CMV) and bean common mosaic virus (BCMV) in the leaves of both Vigna species. CMV from leaves of V. marina and BCMV from V. riukiuensis systemically infected Vigna plants and caused symptoms on leaves. Thus, these viruses are responsible for the symptoms. This is the first report of CMV and BCMV infecting wild species of Vigna in Japan. [ABSTRACT FROM AUTHOR]

The Ty1/copia-like retrotransposon ONSEN is conserved among Brassica species, as well as in beans, including adzuki bean (Vigna angularis (Willd.) Ohwi & Ohashi), which is one of the economically important crops in Japan. ONSEN has acquired a heat-responsive element that is recognized by plant heat stress defense factors, resulting in its transcription and the production of full-length extrachromosomal DNA under conditions with elevated temperatures. DNA methylation plays an important role in regulating the activation of this transposon in plants. Therefore, chemical inhibition of DNA methyltransferases has been utilized to study the effect of DNA methylation on transposon activation. To understand the effect of DNA methylation on ONSEN activation, Arabidopsis thaliana and adzuki bean seedlings were treated with zebularine, which is known to be an effective chemical demethylation agent. The results showed that ONSEN transcription levels were upregulated in zebularine-treated plants. Extrachromosomal DNA of ONSEN also accumulated in the treated plants. [ABSTRACT FROM AUTHOR]

We investigated the physicochemical properties of starches extracted from Vigna angularis variants Noto-dainagon, Kyoto-dainagon, dainagon, and erimo-type adzuki beans. The particle size was larger in the Noto-dainagon starch than in the other starches, but all starches displayed a C-type crystal structure in the X-ray diffraction analysis. The onset and peak temperatures of gelatinization were approximately 7 °C lower in the Noto-dainagon and Kyoto-dainagon starches than in the dainagon and adzuki bean starches. The dainagon and adzuki bean starches also demonstrated lower swelling power at 60 °C than the other starches. The rapid visco-analyser curves of all starches showed no breakdown during the heating process, and the final viscosities of the starches increased with decreasing temperature. The apparent amylose and phosphorus contents were highest in the Noto-dainagon starch (36.6% and 95.6 ppm, respectively). The branched- chain length degree of polymerization 6–12 was lowest in the adzuki bean starch. In vitro and in vivo analyses of the digestive properties indicated that dainagon starch was more indigestible than the other starches. We considered that dainagon starch was a potentially viable health-promoting ingredient. • Noto-dainagon starch had a larger particle size than other starches. • Noto-dainagon and Kyoto-dainagon starches were easily gelatinized. • The rapid visco-analyser curves of all starches showed no breakdown. • Dainagon starch was more indigestible than other starches. [ABSTRACT FROM AUTHOR]

Fatty acid (FA) compositions and molecular species of triacylglycerols (TAG) isolated from total lipids extracted from adzuki beans ( Vigna angularis) were determined with a combination of AgNO3-TLC and GC, and were compared in relation to the content of endogenous antioxidants analyzed by HPLC. δ-Tocopherol was present in the highest concentration (53.7–89.3 mg/kg), and γ-tocopherol in small amounts (11.2–14.8 mg/kg). The main lipid components were phospholipids (72.2–73.4%) and TAG (20.6–21.9%), whilst other components were also present in minor proportions (0.1–3.4%). Eighteen different TAG molecular species were identified and quantified by successive applications of AgNO3-TLC and GC. The main components were SMD (4.6–5.0%), S2T (13.4–16.4%), SD2 (11.8–14.3%), SMT (7.3–8.3%), SDT (9.9–10.6%), D3 (6.9–7.9%), MT2 (5.2–6.3%), D2T (7.0–11.2%), DT2 (7.4–7.6%) and T3 (6.2–7.2%) (where S, M, D, and T denote a saturated FA, a monoene, a diene, and a triene, respectively). No marked difference ( P > 0.05) in the molecular species composition could be observed among the five cultivars. The results could be useful to both consumers and producers for manufacturing traditional adzuki confectionaries in Japan and elsewhere. [ABSTRACT FROM AUTHOR]

Combining high-carbohydrate food with polyphenol-rich food is a possible way of producing slowly digestible starch with beneficial health properties. In Japan, non-glutinous and glutinous rice are cooked with adzuki bean and the colour of the cooked rice is pale red. In this article, we show that (1) the red colour of rice could be attributed to the oxidation of adzuki bean procyanidins, (2) pancreatin-induced starch digestion of the red-coloured non-glutinous rice was slower than white rice and (3) the digestion of amylose and potato starch but not amylopectin became slower by heating with procyanidin B2. Furthermore, the rate of starch digestion of red-coloured rice was not affected by nitrite treatment under simulated gastric conditions. The above results show that procyanidins could bind to amylose independent of the starch source by heating and could suppress starch digestion by α-amylase in the intestine.